'09 Camry Vibration
 

I have a vibration in my 2009 Camry. It is felt mainly in the seat/floor, not the steeringwheel or dash. I had the tires balanced, didn't fix it. Had them do a road force balance, didn't fix it. Then I was told I had a bent rim, replaced it, didn't fix it. Then I was told it was the tires, replaced all four, didn't fix it! Luckily, the great guys at Discount Tire put my old tires back on and didn't charge me a dime. At the end of my rope...

What could be causing this vibration? No noise detected so I don't think it's the bearing. The vibration is not really obviously until I reach 65 MPH. Then between 70 and 80, the vibration is at it's worst. Would appreciate any recommendations.